U.S. Pat. No. 6,113,874 discloses heat recovery methods useful with furnaces employing regenerators wherein a stream of combustion products formed in the furnace is passed through a first regenerator to heat the first regenerator and cool the combustion products, and then a portion of the cooled combustion products is combined with fuel to form a mixture which is passed through a second heated regenerator and where it undergoes an endothermic reaction to form syngas that then passes into the furnace and is combusted.
The present invention is an improvement in the methods disclosed in that patent, whereby it has unexpectedly been found that the efficient heat recovery afforded by these methods can be improved and other benefits described herein can be realized. In particular, the present invention encourages the formation of significant amounts of soot at certain stages, whereas the aforementioned U.S. Pat. No. 6,113,874 teaches that soot is something to be minimized and, if produced, to be removed.